Scott Parker spared West Ham's blushes against Oxford by scoring the winner with a right-foot shot deep into injury time to send the Hammers through to the third round of the Carling Cup.
The match proved to be a test for the Hammers with Oxford bringing good saves from goalkeeper Marek Stech following efforts by James Constable and Asa Hall while Simon Heslop and Harry Worley were narrowly wide.
Parker came close 10 minutes from time while Carlton Cole had an effort ruled out for offside after 88 minutes before the former settled the match in the Premier League side's favour.
Blackpool manager Ian Holloway missed his side's 4-3 humiliation at the hands of League One side MK Dons as Lewis Guy scored an extra-time winner in the round two clash.
The home side led in the first minute through Sam Baldock before Brett Ormerod brought the visitors level after the break. Jermaine Easter then netted twice in as many minutes before a free-kick from Ludovic Sylvestre gave Blackpool a lifeline.
Ormerod also had two close-range efforts disallowed for offside before a late penalty from substitute Charlie Adam took the game into extra-time when Guy struck the winner. Holloway had chosen to miss the game at stadiummk in favour of watching a transfer target elsewhere, leaving his assistant Steve Thompson in charge.
Blackburn's on-loan striker Mame Diouf proved to be the difference between the two sides as he scored a hat-trick to beat Norwich 3-1.
The Senegal international, who arrived from Manchester United earlier this month, marked his full Rovers debut by heading the opener in the 29th minute. Diouf, 22, also hit the crossbar from close range after the interval before stabbing home his second 11 minutes from time and nodding in a third before Jens Berthal Askou's 90th-minute consolation.
Colchester keeper Mark Cousins gifted England international Darren Bent a double as Sunderland eased through with a 2-0 win.
Errors from Cousins allowed Bent to strike after 20 and 37 minutes and secure the Black Cats' first victory of the season. The League One side went close through Anthony Wordsworth and David Perkins ether side of the break, but substitute Martyn Waghorn hit the bar late on.
Ivan Klasnic marked his first start since rejoining Bolton by firing Owen Coyle's much-changed side through 1-0 against Southampton.
The Croatian striker, whose selection was one of nine changes made by Coyle, tucked away a knock-down from former Southampton frontman Kevin Davies with half an hour gone. Bolton were also indebted to a fine display from debutant goalkeeper Adam Bogdan, who kept League One Saints at bay with a string of fine saves from Adam Lallana, Lee Barnard and Jason Puncheon.
Richard Stearman's struck in the final minute of extra-time to give Wolves a 2-1 victory over Southend. Wolves took the lead through Nenad Milijas' first-half penalty after Sam Winnall was fouled by Chris Barker.
Shrimpers captain Craig Easton pulled back a deserved equaliser for the npower League Two side in the 80th minute, but Stearman had the final say after an additional 30 minutes.
Jon Walters helped steer Stoke through with his first goal for the club in a 2-1 win over Shrewsbury.
The former Ipswich forward, who arrived last week, made the breakthrough in the 26th minute. Eleven minutes later Tuncay added a second, both goals coming from headers, while Steve Leslie replied for the League Two side.
Jordi Gomez fired a stunning late free-kick to finally breathe fire into Wigan's season as they cruised to a 2-1 win at Hartlepool.
Sam Collins' third minute own goal immediately eased the pressure on boss Roberto Martinez but Joe Gamble had a fine chance to equalise for the home side. As Hartlepool tired, Gomez slammed his 25-yard free-kick home off the underside of the bar and substitute Victor Moses added the third four minutes from time.
Pablo Ibanez scored his first goal for West Brom as the Baggies won 2-0 at Leyton Orient. Scott McGleish had the best early chance for the npower League One side, but his low strike was turned around the post by Boaz Myhill.
Ibanez - signed from Atletico Madrid in the summer - headed in on 12 minutes for a much-changed Baggies side, with substitute Chris Wood slotting home a second during stoppage time.
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